U.S. patent number 6,421,493 [Application Number 09/585,813] was granted by the patent office on 2002-07-16 for apparatus and method for assembling and aligning a plurality of optical fibers.
This patent grant is currently assigned to Fitel USA Corp.. Invention is credited to Denis E Burek, Muhammed A Shahid, Brandon J West.
United States Patent |
6,421,493 |
Burek , et al. |
July 16, 2002 |
Apparatus and method for assembling and aligning a plurality of
optical fibers
Abstract
Embodiments of the invention include an optical uniform spacing
assembly for aligning a multipitch plurality of optical fibers into
a uniform pitch linear array of optical fibers. The assembly
includes an organizer body having a slot formed therein that
extends longitudinally along the body. A portion of the slot has a
width dimensioned to allow only one optical fiber at a time
therethrough simultaneously and a depth dimensioned to align a
multipitch plurality of optical fibers into a uniform pitch linear
array of optical fibers. The assembly provides sufficient alignment
for transitioning from, e.g., an optical fan-out arrangement such
as a plurality of individual optical fibers to, e.g., an optical
fan-in arrangement such as a ribbon cable arrangement. The assembly
provides a compact, easily assembled apparatus and method for
overcoming size mismatch and other conventional problems associated
with transitioning between differing arrangements. Alternatively,
the spacing assembly includes a transition assembly coupled to the
front end thereof for providing additional alignment to, e.g., a
multipitch array of optical fibers, prior to their alignment within
the organizer body. Also, alternatively, an optical device such as
a multifiber optical connector is coupled to the back end of the
spacing assembly. Suitable multifiber connectors include, e.g., a
MT connector, a MAC connector, or a LMC connector.
Inventors: |
Burek; Denis E (Cumming,
GA), Shahid; Muhammed A (Snellville, GA), West; Brandon
J (Roswell, GA) |
Assignee: |
Fitel USA Corp. (N/A)
|
Family
ID: |
24343065 |
Appl.
No.: |
09/585,813 |
Filed: |
March 24, 2000 |
Current U.S.
Class: |
385/134;
385/137 |
Current CPC
Class: |
G02B
6/3885 (20130101); G02B 6/4471 (20130101); G02B
6/3636 (20130101); G02B 6/3668 (20130101); G02B
6/3839 (20130101) |
Current International
Class: |
G02B
6/44 (20060101); G02B 6/38 (20060101); G02B
6/36 (20060101); G02B 006/00 () |
Field of
Search: |
;385/134,137,136,147,60,65,59,54,71,72,83,139 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sanghavi; Hemang
Assistant Examiner: Knauss; Scott A
Attorney, Agent or Firm: Harman; John M.
Claims
What is claimed is:
1. An optical uniform spacing assembly, comprising: an organizer
body having a slot formed therein and extending longitudinally
along the body, at least a portion of the slot having a width
dimensioned to allow no more than one optical fiber therethrough
simultaneously and at least a portion of the slot having a depth
dimensioned to align a multipitch plurality of optical fibers into
a uniform pitch linear array of optical fibers; and a holddown
dimensioned to fit into at least a portion of the slot and
configured to partially dimension at least a portion of the depth
of at least a portion of the slot.
2. The apparatus as recited in claim 1, wherein the organizer body
includes a front end and a back end, and wherein the front end is a
fan-out end adapted for receiving a multipitch plurality of optical
fibers.
3. The apparatus as recited in claim 1, wherein the organizer body
includes a front end and a back end, and wherein the back end is a
fan-in end adapted for coupling with a multifiber connector.
4. The apparatus as recited in claim 3, wherein the multifiber
connector is selected from the group consisting of MT connector,
LMC connector and MAC connector.
5. The apparatus as recited in claim 1, wherein the organizer body
has a front end and a back end, wherein the slot extends
longitudinally from the front end to the back end and aligns the
plurality of optical fibers at the back end into a ribbon cable
arrangement.
6. The apparatus as recited in claim 1, further comprising a
transition assembly configured for operably coupling to the
organizer body of the optical uniform spacing assembly, wherein the
transition assembly is configured for positioning a plurality of
individual optical fibers into an array of multipitch optical
fibers, and wherein the transition assembly is configured for
providing strain relief to the plurality of optical fibers
positioned therein.
7. The apparatus as recited in claim 6, wherein a portion of the
slot is dimensioned to couple the transition assembly thereto.
8. The apparatus as recited in claim 7, wherein the transition
assembly further comprises: a first housing member having an input
end and an output end; and a second housing member having an input
end and an output end and intermatable with the first housing
member, wherein the input end of the first housing member includes
a first plurality of fins defining a first plurality of grooves
dimensioned to receive a first plurality of multipitch optical
fibers and the input end of the second housing includes a second
plurality of fins defining a second plurality of grooves
dimensioned to receive a second plurality of multipitch optical
fibers, wherein the output end of the first housing member includes
a third plurality of fins defining a third plurality of grooves
dimensioned to receive the first plurality of multipitch optical
fibers from the first plurality of grooves and the output end of
the second housing member includes a fourth plurality of fins
defining a fourth plurality of grooves dimensioned to receive the
second plurality of multipitch optical fibers from the second
plurality o f grooves, wherein, the first and second housing
members are configured in such a way that, when the first and
second housing members are intermated, fins from the first
plurality of fins align between fins from the second plurality of
fins in such a way that optical fibers positioned in the second
plurality of grooves are maintained by the fins from the first
plurality of fins and fins from the second plurality of fins align
between fins from the first plurality of fins in such a way that
optical fibers positioned in the first plurality of grooves are
maintained by the fins from the second plurality of fins, and
wherein, the first and second housing members are configured in
such a way that, when the first and second housing members are
intermated, fins from the third plurality of fins align between
fins from the fourth plurality of fins in such a way that optical
fibers positioned in the fourth plurality of grooves are maintained
by the fins from the third plurality of fins and fins from the
fourth plurality of fins align between fins from the third
plurality of fins in such a way that optical fibers positioned in
the third plurality of grooves are maintained by the fins from the
fourth plurality of fins.
9. The apparatus as recited in claim 1, wherein the slot aligns the
plurality of optical fibers into a linear array of optical fibers
having a uniform pitch of approximately 250 microns (.mu.m)
center-to-center.
10. A method for assembling a multipitch plurality of optical
fibers into a uniform pitch plurality of optical fibers, the method
comprising the steps of: providing an organizing assembly having a
slot dimensioned to radially pass no more than one optical fiber
therethrough and to align a multipitch plurality of optical fibers
into a uniform pitch linear array of optical fibers; providing a
transition assembly configured for coupling to the organizing
assembly and for positioning a plurality of individual optical
fibers into an array of optical fibers, the transition assembly
including a plurality of grooves dimensioned to receive a plurality
of multipitch optical fibers therein; positioning a multipitch
plurality of optical fibers in the transition assembly in such a
way that a portion of the multipitch plurality of optical fibers is
positioned in the transition assembly and a portion of the
multipitch plurality of optical fibers extends from the transition
assembly, wherein the transition assembly provides strain relief to
the portion of the optical fibers positioned therein; coupling the
transition assembly to the organizing assembly, wherein the portion
of the multipitch plurality of optical fibers extending from the
transition assembly is aligned in the slot of the organizing
assembly in such a way that a uniformly pitched linear array of
optical fibers is formed; and coupling a holddown to the organizing
assembly to partially dimension at least a portion of the slot.
11. The method as recited in claim 10, further comprising the step
of coupling a multifiber connector to the organizing assembly.
12. The method as recited in claim 11, wherein the multifiber
connector coupling step further comprises coupling a multifiber
connector selected the group consisting of MT connector, LMC
connector and MAC connector to the organizing assembly.
13. The method as recited in claim 10, wherein the organizing
assembly has a plurality of coupling position features and the
coupling step further comprises coupling the transition subassembly
to one of the plurality of coupling positions formed along the
organizing assembly.
14. The method as recited in claim 10, wherein the plurality of
optical fibers include a coating layer formed thereon and a
protective strength layer formed on the coating layer, and wherein
the portion of the plurality of optical fibers positioned within
the transition assembly comprises coated optical fibers stripped of
their protective strength layers, and wherein the portion of the
plurality of optical fibers positioned and aligned within the
organizing assembly comprises uncoated optical fibers stripped of
their protective strength layer and their coating.
15. An optical waveguide system for transmitting optical energy,
comprising: a first optical device, including a multipitch
plurality of optical waveguides; a second optical device having a
uniform pitch linear array of optical waveguides; an optical
uniform spacing assembly coupled therebetween, wherein the uniform
spacing assembly includes a body having a slot formed therein and
extending longitudinally along the body, at least a portion of the
slot having a width dimensioned to radially pass no more than one
optical fiber therethrough and at least a portion of the slot
having a depth dimensioned to align the multipitch plurality of
optical fibers into a uniform pitch linear array of optical fibers
configured for optically coupling to the second optical device; and
a holddown dimensioned to fit into at least a portion of the slot
and configured to partially dimension at least a portion of the
depth of at least a portion of the slot.
16. The system method as recited in claim 15, wherein the body
includes a front, fan-out end adapted for receiving a multipitch
plurality of optical fibers, and a back, fan-in (ribbonized) end
adapted for coupling with the second optical device.
17. The system method as recited in claim 15, wherein the second
optical device is a multifiber connector.
18. The system method as recited in claim 17, wherein the
multifiber connector is selected from the group consisting of MT
connector, LMC connector and MAC connector.
19. The system method as recited in claim 15, further comprising a
transition assembly configured for operably coupling to the body of
the optical fiber uniform spacing assembly, wherein the transition
assembly is configured for transitioning a plurality of individual
optical fibers into an array of multipitch optical fibers, and
wherein the transition assembly is configured for providing strain
relief to the plurality of optical fibers positioned therein.
20. The system method as recited in claim 15, wherein the body has
a front end and a back end, wherein the slot extends longitudinally
from the front end to the back end and aligns the plurality of
optical fibers at the back end into a ribbon cable arrangement.
21. The system method as recited in claim 15, wherein the slot
aligns the plurality of optical fibers into a linear array of
optical fibers having a uniform pitch of approximately 250 microns
(.mu.m) center-to-center.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to assembly and alignment of multiple optical
fibers. More particularly, the invention relates to assembly
apparatus and methods for aligning optical fibers for
connectorization.
2. Description of the Related Art
The explosive growth in demand for capacity in communications
networks including data networks has spawned an increase in the
number of optical fibers within optical fiber cables and in the
attendant interconnections between the optical fiber cables and the
network nodes. Also, the increasing use of optical fibers for
shorter-haul distances has further prompted a need for optical
cables with larger fiber counts. Such short-haul uses include local
loop applications and delivery of communication services to homes
and offices. Because of these increased demands placed on optical
fiber communication systems, the organization and alignment of
optical fibers, e.g., for interconnection between various optical
devices, has become more important to the overall performance of
the optical system.
Typically, optical fibers are organized into ribbon cables or other
arrangements having highly precise, fixed spatial relationships. An
optical fiber ribbon or ribbon cable includes a plurality of
optical fibers that extend longitudinally and are laterally
adjacent and bound together laterally by a matrix material as a
single, linear array of optical fibers. Optical fiber ribbon cables
typically are connected to other optical devices such as optical
transmitters, receivers or other optical fibers through one or more
optical connectors.
Optical fiber ribbon connectors typically include a metal or
silicon body having an array of grooves dimensioned to position the
ends of the individual optical fibers within the ribbon cable. More
recently, such connectors have been made of plastic. Typically, the
individual fibers are stripped of their protective coating and
secured side by side in the connector grooves. The fibers ends then
are cleaved and polished to form a smooth surface with the
connector endface. The ribbon cable typically is connected to other
optical devices by butt-splicing the connector endface to a similar
surface of the other optical device. In this manner, the use of
ribbon fiber for multi-fiber interconnection simplifies the
connection arrangements, provides fiber strength and stability and
improves the consistency of the spacing between adjacent
fibers.
However, in applications where the optical fibers to be
interconnected have different arrangements or are sized
differently, conventional interconnection devices and methods are
insufficient. For example, in optical fan-in/fan-out arrangements,
the fan-in side typically is characterized by uniform spacing
between one or more linear arrays of optical connections, e.g., a
ribbon fiber arrangement. In contrast, the fan-out side typically
is characterized by a plurality of multi-pitched fibers that often
are of varying size or are sized differently than the fibers of the
fan-in side, which often are sized and spaced in accordance with
conventional, commercial connectors. Quite often, the fan-out side
has a plurality of individual optical fibers connected thereto.
Thus, interconnection between the two disparate arrangements
requires an effective alignment transition therebetween.
Accordingly, it would be desirable to have available
interconnection apparatus and/or methods for transitioning between
different optical fiber arrangements. In this manner, optical fiber
arrangements such as optical ribbon cables are suitable for
connection to optical devices such as optical transmitters, optical
receivers or are interconnected to other optical fibers, regardless
of whether such fibers are in the form of other ribbon cables or
multipitch, multi-fiber arrangements typical of, e.g., fan-out
configurations.
SUMMARY OF THE INVENTION
The invention is embodied in an optical uniform spacing assembly
for aligning a multipitch plurality of optical fibers into a
uniform pitch linear array of optical fibers. The optical uniform
spacing assembly includes an organizer body having a slot formed
therein that extends longitudinally along the body. A portion of
the slot has a width dimensioned to allow only one optical fiber at
a time therethrough simultaneously and a depth dimensioned to align
a multipitch plurality of optical fibers into a uniform pitch
linear array. That is, a portion of the slot has a width only
slightly larger than the diameter of an optical fiber and a depth
that is only slightly larger than the width of a uniform linear
array of optical fibers.
The spacing assembly provides sufficient alignment for
transitioning from, e.g., an optical fan-out arrangement such as a
plurality of individual optical fibers to, e.g., an optical fan-in
arrangement such as a ribbon cable arrangement. The spacing
assembly provides a compact, easily assembled apparatus and method
for overcoming size mismatch and other conventional problems
associated with transitioning between differing arrangements.
Alternatively, the spacing assembly includes a transition assembly
coupled to the front or fan-out end of the organizer for providing
additional alignment to, e.g., a multipitch array of optical
fibers, prior to their alignment within the organizer body. Also,
alternatively, an optical device such as a multifiber optical
connector is coupled to the back or fan-in end of the organizer
body. Suitable multifiber connectors include, e.g., a MT connector,
a MAC connector, or a LMC connector.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1a is a perspective view of an optical fiber uniform spacing
assembly according to an embodiment of the invention coupled to a
transition assembly and coupled to a multifiber connector;
FIG. 1b another perspective view of an optical fiber uniform
spacing assembly shown in FIG. 1a coupled to a transition assembly
and coupled to a multifiber connector;
FIG. 2a is a perspective view of the front end or the fan-out end
of the primary assembly body portion of the optical fiber uniform
spacing assembly according to an embodiment of the invention;
FIG. 2b is a perspective view of the back end or the fan-in end of
the primary assembly body shown in FIG. 2a;
FIG. 2c is a cross-sectional view of the primary assembly body
shown in FIGS. 2a-b taken along the lines 2c--2c of FIG. 2b;
FIG. 3a is a front perspective view of one piece of a two-piece
transition assembly portion of the optical fiber uniform spacing
assembly according to an embodiment of the invention;
FIG. 3b is a back perspective view of the two-piece transition
assembly piece shown in FIG. 3a;
FIG. 4 is a perspective view of the two-piece transition assembly
portion shown in FIGS. 3a-b with a plurality of optical fibers
positioned therein;
FIG. 5a is a front perspective view of a transition assembly
portion of the optical fiber uniform spacing assembly according to
an embodiment of the invention with a plurality of optical fibers
positioned therein;
FIG. 5b is a back perspective view of the transition assembly
portion shown in FIG. 5a;
FIG. 6a is a cross-sectional view of the transition assembly taken
along the lines 6a--6a of FIG. 5a;
FIG. 6b is a cross-sectional view of the transition assembly taken
along the lines 6b--6b of FIG. 5b;
FIG. 7a is a perspective view of the optical fiber uniform spacing
assembly according to an embodiment of the invention showing the
transition assembly coupled to the primary assembly body and the
holddown removed from the primary assembly body;
FIG. 7b is another perspective view of the optical fiber uniform
spacing assembly shown in FIG. 7a showing the transition assembly
coupled to the primary assembly body and the holddown removed from
the primary assembly body;
FIG. 8a is a perspective view of the optical fiber uniform spacing
assembly according to an embodiment of the invention showing the
transition assembly coupled to the primary assembly body and the
holddown positioned in the primary assembly body;
FIG. 8b is another perspective view of the optical fiber uniform
spacing assembly shown in FIG. 8a showing the transition assembly
coupled to the primary assembly body and the holddown positioned in
the primary assembly body;
FIG. 9a is a perspective view of a cover for use in maintaining the
operable position of the holddown in the primary assembly body;
FIG. 9b is a perspective view of the optical fiber uniform spacing
assembly according to an embodiment of the invention showing the
cover of FIG. 9a operably positioned on the primary assembly
body;
FIG. 10a is a perspective view of the optical fiber uniform spacing
assembly according to an embodiment of the invention with a tapered
tube operably coupled to the back end thereof;
FIG. 10b is another perspective view of the optical fiber uniform
spacing assembly shown in FIG. 10a with a tapered tube operably
coupled to the back end thereof; and
FIG. 11 is a simplified block diagram of a method for assembling a
multipitch plurality of optical fibers into a uniform linear array
of optical fibers.
DETAILED DESCRIPTION
In the following description similar components are referred to by
the same reference numeral in order to simplify any sequential
aspect of the drawings and to enhance the understanding of the
invention through the description of the drawings.
Although specific features, configurations and arrangements are
discussed hereinbelow, it should be understood that such is done
for illustrative purposes only. A person skilled in the relevant
art will recognize that other steps, configurations and
arrangements are useful without departing from the spirit and scope
of the invention.
Referring now to FIGS. 1a-b, shown are perspective views of an
optical fiber uniform spacing assembly 10 according to an
embodiment of the invention. The spacing assembly 10 positions and
aligns a first optical device 12 such as a multipitch plurality of
optical fibers into a linear array of uniformly pitched optical
fibers suitable for efficient coupling to a second optical device
14 such as a multifiber connector having a uniform pitch linear
array or optical waveguides (e.g., a ribbon fiber connector). As
will be evident from the discussion hereinbelow, the spacing
assembly 10 provides a compact, easily assembled apparatus and
method for overcoming size mismatch and other conventional problems
associated with transitioning between differing arrangements.
For purposes of discussion in this description, the term "pitch" is
intended to denote the center-to-center spacing between adjacent
optical fibers, e.g., optical fibers within a linear array of
optical fibers typically referred to as a ribbon, ribbon cable,
optical ribbon cable or optical fiber ribbon cable. Also, for
purposes of discussion in this description, "multipitch" refers to
the variable center-to-center spacing between, e.g., adjacent
optical fibers within a plurality of optical fibers. For example, a
multipitch plurality of optical fibers includes a plurality of
loose, individual optical fibers or a set of pre-connectorized
single ended cables. Also, a multipitch plurality of optical fibers
includes, e.g., a fan-out arrangement of optical fibers.
Uniform pitch linear array devices include, e.g., optical fiber
ribbon arrays and ribbon fiber connectors such as the connector 14
shown. Ribbon arrays and ribbon fiber connectors typically have an
established center-to-center spacing between adjacent optical
fibers and/or waveguides (e.g., 250 .mu.m). The multipitch
plurality of optical fibers 12 shown is, e.g., a plurality of
individual or duplex optical fibers connected to or coming from a
fan-out arrangement. Single or duplex cables often come in sizes
much different (e.g., larger) than the fibers in ribbon arrays.
Thus, a transition region often is useful in optically connecting
and transitioning from one size to the other.
The spacing assembly 10 includes a primary assembly body or
organizer 16, a transition assembly 18 and a holddown 19. As will
be discussed in greater detail hereinbelow, the transition assembly
18 typically is a one-piece or two-piece assembly that provides
strain relief to and generally aligns a multipitch plurality of
optical fibers positioned therein. The transition assembly 18 fits
in or operably couples to the organizer 16 at one or more locations
along the body of the organizer 16. The holddown 19 maintains
alignment of the fibers in the organizer 16. The second optical
device 14 is coupled to the organizer 16, e.g., via a coupling tube
21 or other suitable coupling arrangement.
Referring now to FIGS. 2a-b, the organizer 16 is shown. FIG. 2a
shows a perspective view of the organizer 16 from a front end 23,
which also is referred to herein as the fan-out end or the
multipitched optical fiber end. FIG. 2b shows a perspective view of
the organizer 16 from a back end 25, which also is referred to
herein as the fan-in end or the uniformly aligned optical fiber
end. The organizer 16 has a top surface 27 with a slot 29 formed
therein that runs along the length of the organizer 16. The slot
has a first portion 32 that begins at the back end 25 of the
organizer 16 and runs toward the front end 23, and a second portion
34 integral therewith that runs to the front end 23 of the
organizer 16.
According to embodiments of the invention, the first portion 32 of
the slot 29 on the organizer 16 is dimensioned to align a plurality
of optical fibers into a uniform pitch linear array of optical
fibers. That is, the first portion 32 of the slot 29 has a width
that is only slightly larger than the diameter of a polymer coated
optical fiber and a depth that is only slightly larger than the
width of a uniform linear array of coated optical fibers. For
example, for a linear array of 12 optical fibers, each having a
diameter of approximately 250 microns (.mu.m) when stripped of
their protective jackets (including strength members), the first
portion 32 of the slot 29 is approximately 250 .mu.m wide and
approximately 3 millimeters (mm) deep (12.times.250 .mu.m). As will
be understood to those skilled in the art, in practice, the actual
dimensions of the first portion 32 of the slot 29 are just slightly
larger than the given values to allow the optical fibers enough
room to move into their aligned locations.
As the slot 29 runs toward the front end 23 of the organizer 16,
the first portion 32 of the slot 29 becomes the second portion 34
of the slot 29, and thus widens and deepens to dimensions suitable
to accommodate coupling of the transition assembly 18 thereto. See,
e.g., FIG. 2c. The change in depth of the second portion 34 of the
slot 29 is seen, e.g., by observing the depth of the slot 29 at the
back end 25 or the organizer 16 (FIG. 2b) compared to the depth of
the opening of the slot at the front end 23 of the organizer 16
(FIG. 2a). Coupling of the transition assembly 18 to the organizer
16 is discussed in greater detail hereinbelow.
According to an embodiment of the invention, the second portion 34
of the slot 29 has one or more sets of flanged indentations 36
formed therein configured transverse to the longitudinal axis 38 of
the slot 29 to accommodate the transition assembly 18. However,
suitable coupling arrangements other than the flange indentations
36 are possible and should be apparent to those skilled in the
art.
As will be more apparent from discussions hereinbelow, the
organizer 16 holds and stabilizes the transition assembly 18 while
providing further alignment of the optical fibers exiting the
transition assembly 18. Also, the organizer 16 provides a
protective, organized space for the aligned fibers prior to their
emergence from the back end 25 of the organizer 16. Other functions
of the organizer 16 will be apparent to those skilled in the art
from further discussions hereinbelow. For example, organizer 16 is
configured with one or more features (shown generally as 39) useful
in aligning and/or securing the organizer 16 to other devices
within a communications system in which the optical fiber uniform
spacing assembly 10 is used.
The transition assembly 18 (referring back to FIGS. 1a-b) is a
two-piece or one-piece assembly configured to fit in or otherwise
operably couple to the organizer 16, e.g., at its front end 23. The
transition assembly 18 positions and generally aligns a plurality
of optical fibers including a multipitch plurality of optical
fibers. The transition assembly 18 positions the optical fibers
therein in such a way that the transition assembly 18 provides
strain relief to the fibers. The strain relief provided allows the
optical fibers to be more readily aligned, e.g., within the
organizer 16.
Although the transition assembly 18 is shown further and discussed
hereinbelow as being formed by intermating two housing members of
the type shown, e.g., in FIGS. 3a-b, it is within the scope of
embodiment of the invention to have a transition assembly made of a
single piece, or even more than two pieces. Such alternative
embodiments would be apparent to one skilled in the art. For
single-piece transition assemblies, the plurality of optical fibers
are inserted therethrough rather than positioned within individual
housing members that subsequently are intermated to form the
transition assembly 18.
Referring now to FIGS. 3a-b, shown are views from the front (FIG.
3a) and back (FIG. 3b) of one piece or housing member 41 of a
two-piece housing member embodiment of the transition assembly 18.
The housing member 41 is intermatable with a similar piece to form
the transition assembly 18. The housing member 41 has an input or
fan-out end 42 for receiving multipitch optical fibers and an
output or fan-in end 44 for further aligning those optical
fibers.
Formed at the input end 42 of the housing member 41 are a plurality
of fan-out fins 46 (e.g., 7 fan-out fins are shown in FIGS. 3a-b)
forming a corresponding plurality of fan-out grooves 48
therebetween (e.g., 6 fan-out grooves are shown in FIGS. 3a-b). The
fan-out fins 46 are spaced accordingly to define corresponding
grooves dimensioned to receive one or more optical fibers from a
plurality of multipitch optical fibers.
Typically, for fan-out applications, the fan-out grooves 48 are
dimensioned to receive a single, jacketed optical fiber cable.
However, in applications where the optical fibers or other
waveguides at the fan-out end are multiple fiber segments of
optical ribbon cable, e.g., a 2, 4 or 6-fiber segment of a 12-fiber
ribbon cable, the fan-out grooves 48 as defined by the fan-out fins
46 are dimensioned accordingly to receive the multiple fiber
segments. In a typical arrangement, e.g., such as the arrangement
shown in FIGS. 3a-b, the fan-out grooves 48 are dimensioned to
receive an individual coated optical fiber along with its
protective jacket and strength member. Also, although the fan-out
grooves 48 are shown as being generally U-shaped, it is within the
scope of embodiments of the invention for the fan-out grooves to be
any shape suitable for positioning one or more multipitch optical
fibers therein (e.g., V-shaped or semicircular).
Formed at the fan-in or output end 44 is a corresponding array of
fan-in grooves 54 (e.g., 6 fan-in grooves are shown in FIGS. 3a-b)
defined by a plurality of fan-in fins 52 (e.g., 7 fan-in fins are
shown in FIGS. 3a-b). The fan-in grooves 54 typically are
dimensioned to position a single jacketed optical fiber. Also,
similar to the fan-out grooves 48, the fan-in grooves 54 are shown
as being generally U-shaped, yet it is within the scope of
embodiments of the invention for the fan-in grooves 54 to be any
shape suitable for positioning one or more optical fibers therein
(e.g., V-shaped or semicircular).
Referring now to FIG. 4, with continuing reference to FIGS. 3a-b, a
front perspective view of the transition assembly housing member 41
is shown with a plurality of optical fibers 12 operably positioned
therein. According to an embodiment of the invention, the fan-out
and fan-in grooves are dimensioned to receive jacketed optical
fibers. However, as discussed hereinabove, the fins define grooves
that are dimensioned depending on the particular application, as
should be apparent to one skilled in the art.
It should be noted that the optical fibers, upon exiting the fan-in
grooves, are shown stripped of their outer strengthening jackets
(the fibers are shown generally as 13).
Typically, the organizer 16 receives and aligns a plurality of
polymer coated optical fibers, although it is within the scope of
embodiments of the invention for the plurality of optical fibers to
be jacketed upon entering the organizer 16.
The grooves 48, 54 in the housing member 41 are configured such
that optical fibers positioned therein generally form, e.g., a
linear array. As shown in this embodiment, the fan-out grooves 48
are configured in such a way that a 1.times.6 array of optical
fibers is formed when positioning the optical fibers in the fan-out
grooves 48.
Similarly, the fan-in grooves 54 are configured to maintain the
existing arrangement, e.g., the 1.times.6 linear array. However, at
this point in what will ultimately be the transition assembly 18,
the housing member 41 is more concerned with providing strain
relief to the optical fibers rather than accurately aligning
them.
The housing member 41 includes components or features necessary for
intermating with another similarly-configured housing member to
form the transition assembly 18. For example, according to an
embodiment of the invention, the housing member 41 includes a
first, male sidewall 62 and a second, female sidewall 64. The male
sidewall 62 has, e.g., a truncated lip 66 or other feature
configured to connectably engage an opening 68 or other feature
formed in or part of the second, female sidewall 64.
Referring now to FIGS. 5a-b, shown are front and back perspective
views of the transition assembly 18, e.g., when formed by
intermating two housing members of a two-piece transition assembly.
The transition assembly 18 is shown generally from the front or
fan-out end 42 (FIG. 5a) and from the back or fan-in end 44 (FIG.
5b). When intermated, the transition assembly housing members 41
bring together one plurality of optical fibers from the first
housing member and another plurality of optical fibers from the
housing member intermated therewith. Thus, for the housing members
41 shown in FIGS. 3a-b and FIG. 4, the two pluralities of optical
fibers exist generally as a 2.times.6 array of optical fibers.
According to embodiments of the invention, the transition assembly
housing members are configured in such a way that, when intermated
to form the transition assembly 18, the fan-out grooves of the
housing members are shifted slightly with respect to one another.
In this manner, the 2.times.6 array of optical fibers formed when
intermating the housing members is slightly staggered. Such is
seen, e.g., in FIG. 6a, which shows a cross-sectional view of the
transition assembly 18 taken along the lines 6a--6a of FIG. 5a,
i.e., just before the fan-out end 42. Also, the staggered 2.times.6
array is seen in FIG. 6b, which shows a cross-sectional view of the
transition assembly 18 taken along the lines 6b--6b of FIG. 5b,
i.e., just beyond the fan-in end 44 of the transition assembly
18.
The staggered arrangement is such that fan-out fins 46 from one
housing member correspondingly align with fan-out grooves 48 of the
opposing, intermated housing member, e.g., as shown in FIG. 6a. In
this manner, the fan-out fins 46 assist the fan-out grooves 48 in
providing strain relief for the optical fibers positioned in the
fan-out grooves 48 by engaging the particular optical fiber
positioned in the fan-out groove opposite the particular fan-out
fin. A similar arrangement exists between fan-in fins 52 and fan-in
grooves 54 at the back or fan-in end 44 of the transition assembly
18, e.g., as shown in FIG. 6b.
Referring now to FIGS. 7a-b and 8a-b, once the transition assembly
18 is formed and the optical fibers are operably positioned
therein, the transition assembly 18 is coupled to the organizer 16,
e.g., by inserting a portion of the fan-in end 44 of the transition
assembly 18 into a portion of the second portion 34 of the slot 29
formed in the organizer 16. As discussed previously herein, the
slot 29 has features such as the pair of flanged indentations 36
formed therein and dimensioned to receive a portion of the
transition assembly 18. When the transition assembly 18 is coupled
to the organizer 16, e.g., as shown in FIGS. 7a-b, the portion of
the plurality of optical fibers extending out of the fan-in end 44
of the transition assembly 18 fit within the first portion 32 of
the slot 29 and extend out of the back end 25 of the organizer
16.
According to alternative embodiments of the invention, additional
flange indentations are formed in various axial locations along the
slot 29 to allow coupling of the transition assembly 18 at various
axial locations along the organizer 16. Such embodiment is useful,
e.g., if extra fiber length is desired, e.g., for re-working the
connectorized end of the optical fibers (i.e.,
re-connectorization).
According to embodiments of the invention, the slot 29 is
configured in such a way as to interleavingly merge the generally
staggered array of optical fibers extending out the fan-in end 44
of the transition assembly 18 into a linear array. For example, the
slot 29 of the organizer 16 interleavingly merges the 2.times.6
array of optical fibers formed by the transition assembly 18 into a
1.times.12 array. Depending on the coupling arrangement of the back
end 25 of the organizer 16, the optical fibers in the 1.times.12
array either extend out of the slot 29 at the back end 25 of the
organizer 16 (e.g., as shown in FIGS. 7a-b) or, e.g., are
terminated near the back end 25 of the organizer 16 and polished
down to the surface of the back end 25.
For example, if a multifiber optical connector or other suitable
optical device is to be coupled directly to the back end 25 of the
organizer 16, the plurality of fibers aligned in the slot 29 often
will be cleaved and polished to the surface of the back end 25 of
the organizer 16. Otherwise, the plurality of optical fibers extend
out the slot 29 at the back end 25, e.g., as shown in FIGS. 7a-b.
The extending optical fibers are similar in configuration to a
ribbon fiber arrangement due to their relatively close spacing with
respect to one another.
A holddown 19 fits into a holddown feature or indentation 74 formed
in the first portion 32 of the slot 29, e.g., near the back end 25
of the organizer 16. FIGS. 7a-b show the assembly 10 with the
holddown 19 removed from the first portion 32 of the slot 29. FIGS.
8a-b show the assembly 10 with the holddown 19 operably positioned
in the holddown feature 74. The holddown 19 is configured to assist
in aligning the plurality of optical fibers along with the
configuration of the first portion 32 of the slot 29. As discussed
previously herein, the first portion of the slot 29 is just wide
enough to allow passage of a single optical fiber and is just deep
enough to fit a uniform linear array of optical fibers.
The holddown 19, along with the first portion 32 of the slot 29,
transitions the linear array of fibers into a uniform pitch linear
array of optical fibers. More specifically, the dimensions of the
holddown 19 and its operable position within the first portion 32
of the slot 29 define an area that urges the linear array of
optical fibers to have relatively uniform spacing therebetween.
For example, in the arrangement shown in the Figures, the first
portion 32 of the slot 29 has a width of approximately 250 .mu.m
(i.e., the diameter of a polymer coated optical fiber) and a final
depth of approximately 3 mm (i.e., 12 fibers.times.250 .mu.m per
fiber). The holddown 19 is dimensioned to fit relatively snug in
the holddown feature 74, thus maintaining its position therein.
Alternatively, a cover or other suitable device keeps the holddown
19 in place within the holddown feature 74. For example, referring
now to FIGS. 9a-b, a cover 75 is configured to fit securely on the
top surface 27 of the organizer 16 where the holddown 19 fits into
the holddown feature 74. A suitable fastening device or other
feature or set of features is useful in keeping the cover in place
over the holddown 19. For example, the cover 75 has formed therein
a plurality of openings 77 configured to connectable engage a
corresponding plurality of truncated lips 79 formed on the
organizer 16.
Referring now to FIGS. 10a-b, the coupling tube 21 or other
suitable device is coupled to the back end 25 of the organizer 16.
For example, the coupling tube 21 has a tapered portion 76
positioned over the portion of the linear array of optical fibers
13 extending from the back end 25 of the organizer 16 and a linear
array portion 78 for maintaining the linear array of optical fibers
13 extending from the back end 25 of the organizer 16. The tapered
portion 76 of the coupling tube 21 is coupled to the back end 25 of
the organizer 16, e.g., in a suitable manner. The linear array
portion 78 of the coupling tube 21 further couples the organizer 16
to a second optical device, e.g., a ribbonized connector or other
suitable multifiber connector, such as the multifiber connector 14
shown in FIGS. 1a-b. Suitable connectors include, e.g., MT
connectors, MAC connectors, LMC connectors or other suitable
multifiber optical connectors. Such connectors are discussed, e.g.,
in U.S. Pat. No. 5,388,174 and U.S. Pat. No. 5,603,870.
Referring now to FIG. 11, a method 80 for assembling a multipitch
plurality of optical fibers into a uniform linear array of optical
fibers is shown. The method 80 includes a first step 82 of
providing the organizer 16. As discussed previously herein, the
organizer 16 has a slot 29 with a width slightly larger than the
diameter of an optical fiber and a depth slightly larger than the
width of a uniform linear array of optical fibers. Thus, the slot
29 is dimensioned to organize optical fibers positioned therein
into a linear array of optical fibers.
The method includes another step 84 of providing the transition
assembly 18. The transition assembly 18 is one-piece or two-piece
assembly configured for providing strain relief to a multipitch
plurality of optical fibers positioned therein. Although the
transition assembly 18 generally is shown and discussed herein as a
two-piece assembly, it is within the scope of embodiments of the
invention for the transition assembly 18 to be a one-piece
assembly.
The next step 86 of the method 80 is to position a plurality of
optical fibers in the transition assembly 18. For a one-piece
transition assembly, the optical fibers are inserted or otherwise
positioned in the transition assembly. For a two-piece transition
assembly 18, the step 86 includes initially positioning optical
fibers in the fan-out grooves 48 defined by the fan-out fins 46 at
the fan-out 42 of the housing members 41 (e.g., as shown in FIG.
4). Once the optical fibers are positioned in the grooves of the
housing members 41, for a two-piece transition assembly 18, the
transition assembly housing members 41 are coupled together to form
the transition assembly 18 with the optical fibers positioned
therein, e.g., as shown in FIGS. 5a-b.
Typically, the portion of the optical fiber to be positioned in the
transition assembly 18 is jacketed and the portion of the optical
fiber that extends beyond the fan-in end 44 of the transition
assembly 18 is stripped of its jacket. However, as discussed
previously herein, the grooves 48, 54 in the transition assembly 18
are dimensioned accordingly to the dimensions of the one or more
optical fibers to be positioned therein. Thus, it is within the
scope of embodiments of the invention to position optical fibers
having strength members in grooves dimensioned accordingly.
The next step 88 in the method 80 is to couple the transition
assembly 18 to the organizer 16. For example, the fan-in end 44 of
the transition assembly 18 is configured to fit into a portion of
the slot 29 in the front end 23 of the organizer 16. Alternative
coupling arrangements also are possible, as discussed hereinabove.
The coupling step 88 positions the array of optical fibers
positioned in and extending from the transition assembly 18 into
the slot 29 of the organizer 16. As discussed previously herein, a
portion of the slot 29 is dimensioned to align the array of optical
fibers into a linear array of optical fibers.
The next step 92 is to couple the holddown 19 to the organizer 16,
e.g., as discussed hereinabove in connection with FIGS. 7a-b and
FIGS. 8a-b. According to embodiments of the invention, the holddown
19 is configured and dimensioned to fit into a portion of the slot
29 of the organizer 16 where the linear array of optical fibers are
positioned. When operably positioned in the organizer 16, the
holddown 19 works with the slot 29 to establish a uniform spacing
between adjacent optical fibers in the linear array of optical
fibers positioned in the slot 29. The result is a uniform pitch,
linear of array of fibers at the back end 25 of the organizer
16.
Alternatively, an additional step 94 is to couple a multifiber
connector 14 or other suitable optical device to the organizer 16,
e.g., at the back end 25 thereof. For example, a multifiber
connector such as a MT connector, LMC connector or MAC connector is
coupled to the organizer 16, e.g., as shown in FIGS. 1a-b. In such
arrangements, the coupling tube 21 is used to facilitate coupling
the uniform pitch linear array of optical fibers extending from the
back end 25 of the organizer 16 to the multifiber connector 14. As
discussed previously herein, other suitable coupling arrangements
are within the scope of embodiments of the invention.
It will be apparent to those skilled in the art that many changes
and substitutions can be made to the embodiments of the assembly
apparatus and methods herein described without departing from the
spirit and scope of the invention as defined by the appended claims
and their full scope of equivalents.
* * * * *